朱集煤矿泥岩的流变试验与本构模型研究

Rheological Test and Constitutive Model of Mudstone of Zhuji Coal Mine

巷道等地下工程围岩的蠕变极大地影响着工程的稳定性,正确认识岩石的流变特性可以使岩土工程的设计、施工和运行更加安全可靠。以朱集煤矿泥岩为研究对象,采用分级加载方式,进行单轴弹黏塑性流变试验,借助Origin软件对流变试验数据进行深入分析,研究该岩样各级荷载作用下的轴向蠕变规律,并分别采用线性的Burgers模型和七元件非线性黏弹塑性流变模型(河海模型)对轴向蠕变曲线进行拟合,确定流变模型的力学参数。将拟合曲线与试验曲线对比分析,结果表明:应力水平较低时,2种模型均能较好地反映蠕变过程;当应力达到长期强度后,七元件非线性黏弹塑性流变模型(河海模型)能较好地反映泥岩岩样流变的3个阶段,而Burgers模型偏差较大。

The stability of underground projects like roadway tunnel is greatly affected by the rheology of surrounding rock.A correct understanding of the rheological properties of rock is beneficial to the design,construction and op-eration of geotechnical engineering.The axial rheology regularity of mudstone sample collected from Zhuji coal mine was researched as an example.Uniaxial visco-elasto-plasticity rheological tests were carried out by step loading, and the Origin software was employed to analyse the test data in depth.Furthermore,the axial rheology curves were fitted using Burgers model and the seven-component nonlinear visco-elasto-plastic rheological model,also known as Hohai model,to determine the mechanical parameters of rheological models.Comparison between the fitting curves and the test curve shows that two rheological models could both reflect the creep process at low stress level;but the Hohai model could reflect the three rheological stages more accurately whereas the Burgers model has large devia-tions when the stress approaches the long-term strength.